Standardized multimedia services based on packet-switched Internet Protocol (IP) networks are recently being developed. For example, Multimedia Telephony Service for IP Multimedia System (MTSI), herein also referred to as Multimedia Telephony, is an IP-based multimedia telephony service being developed by the Third-Generation Partnership Project (3GPP) for mobile communications. See 3GPP TS 26.114 V7.5.0, “Technical Specification Group Services and System Aspects IP Multimedia Subsystem (IMS); Multimedia Telephony; Media handling and interaction,” and 3GPP TS 29.163 V8.3.0, “Technical Specification Group Core Network and Terminals; Interworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networks (Release 8),” hereinafter referred to as the “3GPP specification,” the contents of which are herein incorporated by reference in their entirety. A “Packet switched Video Telephony (PSVT)” specification (C.S0055-A v10), the contents of which are also incorporated by reference herein in their entirety, has also been developed by the Third Generation Partnership Project 2 (3GPP2). Packet-switched multimedia telephony is expected to take advantage of the flexible data transport mechanisms afforded by the Internet Protocol (IP), while providing a user experience equivalent to or better than corresponding circuit-switched telephony services.
When sending media from a packet-switched terminal (such as a 3GPP MTSI terminal or a 3GPP2 PSVT terminal) to a circuit-switched terminal (such as a 3GPP CSVT terminal/3G-324M terminal), an interworking node such as a media gateway is called upon to perform interworking between the circuit-switched (CS) and packet-switched (PS) protocols. To deliver media packets from the PS domain, which generally exhibit wide size variation, over fixed-bandwidth CS domain channels, the media gateway may use data packet (e.g., video and/or audio) reformatting mechanisms such as re-shaping buffers, fragmentation, and re-assembly to transport the packets over the circuit switched network. During a telephony session, such reformatting mechanisms may undesirably cause the communications to violate audio-visual (lip) synchronization requirements, and/or degrade the quality of service by introducing additional end-to-end delay between the terminals.
It would therefore be desirable to provide techniques to signal to a PS terminal the maximum packet size limitations on data packets that can be transported without inefficient reformatting. It would further be desirable to provide techniques to allow the PS terminal to adjust the processing of its data packets depending on such maximum packet size limitations, so as to minimize the reformatting of data packets by the interworking node.